CVE-2026-87994 — Open WebUI: Channel members can overwrite another member's message via the chat completions endpoint
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.5 until 0.11.1, the channel branch of chat_completion in backend/open_webui/main.p…
Published: 2026-09-09 · CVSS: 4.3 · CVSS 3.1
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.5 until 0.11.1, the channel branch of chat_completion in backend/open_webui/main.py checked channel write access and channel membership for a supplied message_id but did not verify that the calling user authored the targeted message. A channel member could use the chat completions endpoint to replace another member's message while preserving the victim as the stored author, altering the conversation record without gaining access to other channels. This issue is fixed in version 0.11.1.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7